Means for supporting the electrodes of thermionic devices



Sept. 27, 1932.. ROUND E 1,879,514

' MEANS FOR SUPPORTING .THE ELECTRODES OF THERMIONIC DEVICES OriginalFiled Feb. 23, 1922 INVENTOR H. J. ROUND AND BY W. J. PIC N ATTORNEYstructed of quartz.

Original application filed February 28,

Patented Sept. 21, 1932.

UNITED, STATES PATENT OFFICE HENRY JOSEPH ROUND, 0] MUSWELL HILL,LONDON, AND WILLIAM JAMES PICKEI,

' OF SOUTHEND-ON-SEA, ENGLAND, ASSIGNORS TO RADIO CORPORATION OFAMERICA,

A CORPORATION OF DELAWARE MEANS FOR SUPPORTING THE ELECTRODES OFTEERMIONIC DEVICE 1922, Serial No. 538,512, and in Great Britain larch$1, 1921.

c Divided and this applicationfiled September 25, 1929. Serial No.894,949.

. as possible and at the same time it is necessary that they should beeffectively insulated from one another.

The object of this invention is to provide improved means for supportingand insulating the electrodes.

J According to the novel disclosure in our United States applicationSerial No. 538,512, filed Feb. 23, 1922, of which application this is adivision an electrode of a thermionic device is supported and insulatedby means of a support made of quartz. Preferably the uartz supportconsists of a stem surrounded ior a considerable portionof its length bya cylindrical part which'is preferably also con- On-to each end of thestem may fit supports or connections of metal. It often happens thatseveral electrodes are supported on various parts of the glassof,

which the containing vessel -is constructed,

the glass in between the points on which the electrodes are supportedbeing used to insulate the electrodes from one another. It has beenfound that the insulation of the glass between the various electrodesbecomes insuflicient owing either to the temperature to which the glassis raised or toa metallic deposit upon the inside of the lass or to-bothcircumstances. ."In order to bviate this difficulty in accordance withthe invention disclosed in the present application, asheet or sheets ofmica is or are interposed between the electrode and the glass on whichit is si1p-' ported. In some cases it may be suflicient to employ asingle sheet or layer of mica, but it is preferable to employ twoadjacent layers having between them a space of considerable lengthcompared to its width, so that no metallic deposit can be formed uponthe inner surfaces of the mica. 1

Our invention is illustrated by the drawin in which %igure 1 shows avalve the electrodes of which are supported by quartz supports; I Figure2 shows a fragmentary view of. a thermionic device having a layer ofmica around the stem; and I Figure 3 is amodification of Figure 2.

grid 3 are supported on a reentrant glass'stem 4 at one end of theclosure 1 in a known manner, and the cylindrical anode G is supportedsure member 1 in which 'the filament 2 and at 5 on a reentrant stem 6 atthe other end of the closure 1 also in a known manner.' In

order to retain the anode C correctly spaced in position with res ct tothe rid 3 the upper end of the ano e is provideiwith supports D (usuallythree) attached to arms -E carried by the supports F for the gridthrough a supporting frame or ring G. The ring Ur is in turn carried bythe supports F for-the grid. Quartz insulators B serve as theconnectiens between the corresponding parts D- and E. The ends of D andE ar usuallymade hollow and fit tightly over the" stems A of thequartzsupports as more clearly shown in the parent application abovementioned.

Figure 2 shows part of a valve in which an electrode H is supported froma glass stem withthe'interp'osition of a piece of mica J. It will beunderstood that the electrode C of Figure 1 may likewise be supportedfrom the glass stem or reentrant portion 6 with the interposition of apiece of mica. The mica J interposed between the electrode and the glassclosure increases the insulation between the electrodes of, the tube;

Figure 3 is a similar view showing two cylindrical pieces of mica J andK; the piece J is considerably shorter than the piece K so that -spacesL are formed at each end between the outer piece K and the glass. Inoperation metallic radiation from the cathode cannot form a metallicdeposit on the inner surface of mica or glass forming the spaces asdescribed above. Thus, the insulation of the'electrode supported bypieces J and K is insured. This in turn increases the life andefficiency of the tube. a

We claim:

1. In a thermionic devlce, a glass envelope having a reentrant portion,an electrode supporting member mounted upon said reentrant portion, anelectrode carried by said member, andan insultor of mica interposedbetween 2 reverie said supporting member and the reentrant f portio it2. In a thermionic device, a glass envelope having a reentrant portion,electrode sup- 5 porting means comprising a ring member mounted uponsaid reentrant portion, an electrode carried by said ring member, and asheet of mica interposed between said reentrant portion and said ringmember.

3. In a thermionic device, a glass envelope having a reentrant stem, asheet of mica carried thereby, a second sheet of mica carried by saidfirst named sheet, said second sheet of mica being of greater width thansaid first sheet, and an electrode carried by said second sheet of mica.

4. In a thermionic device, an evacuated envelope having a reentrantstem, electrode supporting means comprising a ring member clamped uponsaid reentrant stem, an electrode carried by said ring member, and apair of sheets of insulating material interposed between said reentrantstem and said ring member, the outer sheet of insulating materialadjacent the ring member being wider than the inner sheet adjacent therecntrant stem and having a portion at each end which extends beyond thecorresponding end of the inner sheet, whereby at each end of the innersheet there is formed an annular space between each extended portion ofthe outer sheet and the reentrant stem.

HENRY JOSEPH ROUND.

WILLIAM JAMES PICKEN.

